The development of atom interferometry over the last two decades has given rise to new insights into the tenets of quantum mechanics as well as to ultra-high accuracy sensors for fundamental physics and technological applications. Examples range from the creation of momentum state superpositions by accurate momentum transfer of laser photons allowing high precision measurements of rotation, acceleration and gravity, to the splitting of trapped ultracold atoms by local potential barriers allowing the investigation of fundamental properties of quantum systems of a few or many particles, such as decoherence and entanglement.
One of the tools for atom interferometry is the atom chip. The high level of spatial and temporal control of local fields which is facilitated by the atom chip has made it an ideal tool for the splitting of a Bose-Einstein condensate (BEC) into a double well potential by a combination of static magnetic fields with radio frequency (RF) or microwave fields. Pure static fields or light fields have also been used. However, practical atom chip schemes for interferometry with a wide dynamic range and versatile geometries are still very much sought-after. Such schemes may enable, for example, sensitive probing of classical or quantum properties of solid state nano-scale devices and surface physics. This is expected to enhance considerably the power of non-interferometric measurements with ultracold atoms on a chip, which have already contributed, for example, to the study of long-range order of current fluctuations in thin films, the Casimir-Polder force and Johnson noise from a surface. In addition, interferometry integrated on a chip is a crucial step towards the development of miniature rotation, acceleration and gravitational sensors based on guided matter-waves.
The disclosed technique follows one of the earliest attempts to envision atom interferometry. The idea of using the Stern-Gerlach (SG) effect, which has become a paradigm of quantum mechanics, as a basis for interferometry was considered shortly after its discovery, almost a century ago. It was generally judged to be impractical due to the extreme accuracy which would be required. The systems and methods of the present invention demonstrate spatial interference fringes with a measurable phase stability, originating from spatially separated paths in SG interferometry.